A variety of methods are known for controlling braking systems of towed equipment such as trailers and towed vehicles. In many cases, braking of towed equipment occurs by activation of controllers located in the towing vehicle.
A known system uses electric brakes on the wheels of towed equipment such as utility trailers, boat trailers, and recreational vehicle trailers to provide needed stopping power. Electric brakes attached to a towed trailer, for example, typically use electric solenoids and/or magnets responsive to an electric brake controller mounted in the towing vehicle for activation from a position that is readily accessible to the driver.
If activated by a proportional controller, trailer brakes are generally electronically activated in response to the degree of slowing of the towing vehicle. Depending on the rate of deceleration, a brake controller sends a signal to apply the brakes of the trailer. The proportional controller can utilize a variety of different sensors to detect changes in inertia of the trailer and towing vehicle, force applied via the towing vehicle's brake system, or position of the brake pedal in the towed vehicle. An example of one type of proportional brake controller is presented in the disclosure of U.S. Pat. No. 7,058,499 to Kissel, which patent, is incorporated in its entirety herein by reference. If a time based controller is utilized instead of a proportional controller, the trailer brakes are generally electronically activated based on predefined power curve once the vehicle brakes are activated. The time based controller utilizes the same power curve every time the brake is actuated. Thus, it is independent from the towing vehicle's and/or the trailer's deceleration.
Popular types of trailer brake control devices include proportional controllers. Common sensing means for proportional controllers include a dynamic accelerometer in the form of a pendulum that measures the force of braking, or deceleration rate of the towing vehicle. In response to a change in these characteristics, the brake controller provides electrical power to apply proportional braking to the towed equipment. The pendulum senses force variation by the degree to which the pendulum swings from a default position. As pendulum displacement increases the proportional controller increases the force applied to the brakes.
Another function of the sensing means, represented by a dynamic accelerometer, is responding to variation of inclination of the towing vehicle. In other words, the sensing means reacts as the towing vehicle traverses an uphill or downhill grade. Whether measuring towing vehicle inclination or rate of deceleration, control signals passing from the accelerometer sensing means to the brake controller produce a proportionate brake amperage output signal with supply of electrical power to control the braking force applied to the brakes of the towed equipment. As expected, the brake amperage output signal increases for downhill grades and is minimal when the vehicle negotiates uphill grades.
Installation of trailer brake controllers typically requires wiring for electrical connection to the power source of the towing vehicle, to the brake lights of the towing vehicle and to the brakes of the towed trailer or vehicle. Often, wire connections used to carry power from the battery to the controller and amplified power from the controller to the brakes are arranged such the wire is of a heavier gauge wire than other wires used with the system. Other wires provide connection to ground—the ground wire usually being the same size as the above mentioned wires—and to brake lights in the controller circuit.